The specific objective of this contract is to evaluate, in an animal model, the development of tolerance to the anticonvulsant activity of unknown benzodiazepine compounds. The animal model, which was developed in the mouse species using pentylenetetrazol induced clonic seizures, shall be used for all evaluations. It is estimated that he Contractor shall be required to evaluate 10-30 compounds during the two year period of the contract. The benzodiazepine compounds to be tested shall be supplied by the NINDS.